Fluorinated organic iodides



United States Patent 3,118,004 FLUORINATED ORGANIC IODHDES Murray Hauptschein, Glenside, and Robert E. Oesteriing,

Flourtown, Pa, assiwors to Penusalt Chemicals Corporation, Philadelphia, Pa, a corporation of Pennsylvania No Drawing. Filed May 23, 1962, Ser. No. 196,918 Claims. (Cl. 260-644) This invention relates to novel fiuorinated nitroiodides. The, new compounds of the invention are those represented by the general formula:

where R is selected from the class consisting of hydrogen, fluorine, perfiuoroalkyl radicals, and fluorohydroalkyl radicals. As used herein perfiuoroalkyl means an alkyl radical containing only carbon and fluorine and fiuorohydroalkyl means an alkyl radical containing only carbon, fluorine and hydrogen wherein the molar ratio of fluorine to hydrogen is at least 121.

Particularly preferred are the compounds where R is hydrogen or flourine, iie. the compounds ICF CH NO and IOF CHFNO Where R is perfluoroalkyl or fluorohydroalkyl, the radical prefeably contains from 1 to carbon atoms and most desirably from 1 to 6 carbon atoms.

The compounds of the invention are p epared by reacting a fiuorinated olefin of the formula OF =OHR, where R is as defined above, with dinitrogen tetroxide (N 0 in the presence of iodine. The reaction may be represented as follows:

Usually, variable amounts of the reverse addition product are formed concurrently according to the following:

Also, in some cases variable amounts of an iodo nitrite or nitrate are formed which readily hydrolyses to the corresponding acid. Thus, e.-g.

ICHRCFzONO(0r ICHRCF2ONO2) The reaction may be carried out at temperatures ranging from about 0 to 100 C., preferably 20 to 50 C., andat pressures ranging from atmospheric to moderately elevated pressures ranging up to e.g. 1000 lbs/in. depending on the reaction temperature and volatility of the reactants. The reaction time is not critical and generally reaction periods range from a few minutes to a day. The molar ratios of the reactants are not critical and may vary widely. A stoichiometric excess of iodine is preferred, while the ratio of N 0 to olefin may vary e.g. from 3:1 to 1:3.

The reaction is desirably carried out in the presence of a solvent which is unreactive to N 0 under the reaction conditions. P-reterred are the halogenated solvents, particularly the chlorinated or chlorofiuorinated solvents such as chloroform, methylene chloride, carbon tetrachloride, trichlorotrifluoroethane, etc. The amount of solvent is not critical and generally may be used in amounts ranging from 100 to 1000 milliliters per mole of olefin. Desirably, the reaction is carried out under substantially anhydrous conditions to avoid reactions between N O and water and the possibility of other side reactions.

As is well known, dinitrogen tetroxide (N 0 is probably an equilibrium mixture of N 0,, with various other forms of nitrogen oxides, particularly N0 whose composition changes depending principally upon the temperature. This behavior of N 0 is described, e.g. by I. L. Riebsomer in Chemical Reviews, vol. 36, No. 2, April 1945, pp. 157 et seq. As used herein the term dinitrogen tetroxide (N 0 is intended to include the various equilibrium mixtures that are obtained under the reaction conditions specified herein.

Where it is desired to minimize the production of nitrites or nitrates, the reaction is preferably carried out by adding the dinitrogen tetroxide slowly to a mixture of the iodine and olefin such that the iodine and olefin are always in excess. The formation of the nitrite 0r nitrate is believed to occur more readily in the presence of excess N 0 Typical examples of percursor olefins and the nitroiodides that are obtained therefrom in accordance with the invention are the following:

Percursor oleiins of the type OF CHR where R is periiuoroalkyl or fluorohydroalkyl are prepared in accordance with the procedures described in copending application Serial No. 53,878, filed September 6, 1960, of Murray Hauptschein et al.

The compounds of the invention are characterized by the ease with which they react with alkanols to form fiuorinated nitroethers. For example, ethyl alcohol reacts with ICF CH NO as follows:

Reactions of this type (which are disclosed in more detail in copending application of Murray Hauptschein and Milton Braid, Serial Number 198,464, filed May 29, 1962, entitled Flourinated Organic Ethers) are believed to proceed by the elimination of H1 from the alpha and beta carbon atoms to form a terminal nitroole'fin to which the alcohol then adds. This reaction is unique to the nitroiodides of the invention containing a terminal CF I group and a beta hydrogen atom.

In addition to serving as intermediates for the preparation of fiuorinated nitroethers as indicated above, the compounds of the invention are also useful for the preparation of fluorinated nitro compounds of the general formula CF CHRNO by the reaction of the corresponding iodide with an alkali metal fluoride. For example, the nitroiodide ICF CH NO reacts with sodium fluoride in accordance with the following:

The compounds of the invention are also useful as soil lumigants, insecticides, herbicides, de-foliants and as antiseptics providing a slow release of iodine.

The following examples illustrate several specific embodiments of the invention:

Example 1 PREPARATION OF ICF CH2NOs A stainless steel autoclave of 1400 milliliters capacity is charged with 500 milliliters of methylene chloride, 92 g. (1.0 mole) of dinitrogen tetroxide and 38-1 g. (1.5 moles) of iodine, connected to a cylinder of vinylidene fluoride, and placed on a shaking apparatus. Vinylidene fluoride at a pressure of 250 lbs/in. gage is introduced Patented Jan. 14, 1964 into the autoclave at room temperature. Within five to ten minutes the autoclave pressure drops to less than 100 lbs/in. gage. The autoclave is repressured with vinylidene fluoride several additional times over a period of about 4 hours until the pressure remains constant at 200 lbs/in. gage. During this procedure, the autoclave temperature remains at from 25 to 30 C., very little heat of reaction being noticeable. The autoclave is vented and the contents filtered to remove unreacted iodide. The methylene chloride solution is washed with aqueous sodium bisulfite until all iodine color is removed, giving a pale yellow solution. The solution is separated from the water wash and dried over anhydrous magnesium sulfate after which the methylene chloride is removed by distillation and the product vacuum distilled to give 161 g. of product having a boiling range of from 65 to 70 C. at 20 mm. Hg.

Analysis of this product by vapor-liquid chromatography and mass spectroscopy shows it to consist of the isomers ICF CH NO and l'CH CF NO in about a 3:1 ratio.

A sample of pure ICF CH NO having a boiling point of 61C. at 11 mm. Hg and of 30 C. at 1 mm. Hg, and a refractive index n 1.4750, analyzed as follows:

Calculated for: C H F INO C, 10.13; H, 0.85; N, 5.91. Found: C, 10.13; H, 0.87; N, 5.97.

The infrared spectrum of ICF CH NO (liquid) displays the following absorption bands: 3.27 1. (medium), 336p. (medium), 3.42 1. (medium), 6.37,u (very, very strong), 7.08 (very strong), 7.31 (very strong), 7.51 (very strong), 8.06 (very strong), 850 (very strong), 902 (very strong), 9.58 (very strong), 10.57 (very strong), 1098 (very strong), 11.23 (very strong), 11.96 t (strong), 13.17p. (strong), 15+,u. (strong). The peaks at 6.37 and at 7.31 correspond to the asymmetric NO and symmetric N stretching vibrations, respectively, of the --CH NO group.

The ultraviolet spectrum of ICF CH NO taken in isooctane solution has a maximum absorption at 270 ring.

A sample of pure ICH CF NO having a boiling point of about 50 C. at mm. Hg has an infrared spectrum with the following absorption bands: 3.27; (medium); 3.35 (medium); 3.40, (medium); 6.28 (very, very strong); 7.09 (strong); 7.40 (very strong); 7.76,u (very strong); 7.96 (very strong); 8.51 1. (strong); 8.88 s (very strong); 9.36 1. (very strong); 1015,11, (very strong); 11.82 (very strong); 13.47 (very strong); 1455 (strong). The peaks at 6.28, and at 7.40 4. correspond to the asymmetric NO and symmetric N0 stretching vibrations, respectively, of the CF NO group.

The ultraviolet spectrum of the isomer ICH CF NO taken in isooctane solution has a maximum absorption at 267 Ill/L.

Example 2 PREPARATION OF CFsCHsNO FROM ICFsCHzNOz The nitroiodide I-CF CH NO is converted to 1,1,1-trifluoro-2-nitroethane in good yield by the following procedure:

A mixture of milliliters of dry tetramethylene sulfone, 9.3 g. (0.04 mole) of ICF CH NO and 3 g. of dry sodium fluoride (0.07 mole) is stirred at 100 C. for 1.5 hours. The reaction mixture is then diluted with 200 milliliters of cold water and steam distilled giving a pale yellow oil which is separated and dried over anhydrous magnesium sulfate. A yield of 3.5 g. (68%) of crude CF CH NO is obtained which on distillation at atmospheric pressure gives a pure colorless liquid, 1,1,1-trifluoro-2-nitroethane, boiling at 96 C. Analysis.Calculated for: C H F NO N, 10.86. Found: N, 10.99.

The infrared spectrum (liquid) shows the characteristic asymmetric N0 vibration at 634 and the symmetric N0 vibration at 733g. The ultraviolet spectrum of CF -CH NO taken in isooctane had a maximum absorption of low intensity at 277 my.

The above procedure provides an improved route to the compound CF CI-I NO Example 3 PREPARATION OF ICFzCHzNOz A 300 milliliter stainless steel autoclave is charged with 100 milliliters of methylene chloride, 51 g. (0.55 mole) of N 0 and 64 g. (1 mole) of vinylidene fluoride. The autoclave and contents are shaken at room temperature for 30 hours. After venting the autoclave, the methylene chloride solution is Washed with water and aqueous sodium bisulfite. The methylene chloride solution is then separated from the water wash, dried and distilled to give 34 g. of crude C H F NO I, mostly ICF CH NO The water and sodium bisulfite Washed from this run are independently extracted with diethylether. From these ether extracts (after drying and removal of ether by distillation) there is obtained 15 g. of iodoacetic acid CH ICOOH, melting at -81 C., the infrared spectrum of which was identical to an authentic sample. In addition, 16 g. of CH ICOOH are found in the residue after vacuum distillation of the nitroiodide. The iodoaeetic acid probably results from the formation of a nitrite (or nitrate) by-product which is subsequently hydrolyzed to the acid in accordance with the following:

H2O ICHzCFzONO (0r ICHzCFzONOz) H2O ICHzC FsOI-I ICHaCOOH Example 4 PREPARATION OF ICFacHzNo-z This example illustrates a procedure for adding N 0 slowly to a mixture of iodine and olefin to minimize the production of nitrite or nitrate. A 300 milliliter stainless steel autoclave is charged with 155 g. (0.61 mole) of iodine crystals; 75 milliliters of CH Cl and 64 g. (1.0 mole) of OF CH A stainless steel cylinder is charged with 51 g. (0.55 mole) of N 0 and 25 milliliters of CH Cl The CH CI solution of N 0 is pumped slowly into the autoclave loaded with the iodine and CF =CH over a period of about 16 hours while shaking the autoclave at room temperature. After venting the autoclave and removal of about 68 g. of solid iodine, the methylene chloride solution is washed with water and then washed with an aqueous solution of sodium bisulfite, after which the solution is dried over anhydrous magnesium sulfate. The methylene chloride is then removed by distillation to give a yield of 97 g. of a red liquid. Fractional distillation of this product shows it to consist mostly of the isomer ICF CH NO and minor amounts of the reverse addition product ICH CF NO There was recovered from this run only 3 g. of iodoacetic acid.

Example 5 PREPARATION OF ICFzCHzNOz The procedure of Example 1 is repeated in a 300 milliliter stainless steel autoclave charged with 64 g. (1 mole) of vinylidene fluoride, 26 g. (0.28 mole) of N 0 77 g. (0.30 mole) of iodine and 100 milliliters of carbon tetrachloride. The entire charge of vinylidene fluoride is pressured into the autoclave and the autoclave and contents are shaken for 25 hours. There is obtained 9 g. of the desired product ICF CH NO Example 6 PREPARATION OF ICF CHFNO:

Following the procedures of Example 1, triiluoroethylene CF CHF is pressured into a 1400 milliliter stainless steel autoclave containing 1 mole of N 0 1.5 moles of iodine and 500 milliliters of methylene chloride, and is shaken at room temperature for 10 hours. After working up the product as described in Example 1, the nitroiodide ICF CHFNO is obtained.

Example 7 PREPARATION OF ICFzCH (N02) CFs A 300 milliliter stainless steel autoclave is charged with 0.3 mole of CF =CHCF 0.3 mole of N 0 0.5 mole of iodine and 100 milliliters of methylene chloride, after which the autoclave is heated With shaking for 20 hours at a temperature of 80 C. After Working up the product as described in the previous examples, there is obtained the nitroiodide IOF CH-(NO )CF Example 8 PREPARATION OF ICF2CII(NO2)CF CH2CaF7 A 300 milliliter stainless steel autoclave .is charged with 0.2 mole of the olefin CF -Cl-lCF cll C F 0.2 mole of N 0 0.4 mole of iodine and 80 milliliters of methylene chloride, and heated with shaking at a temperature of 80 C. for 20 hours. The liquid product from the autoclave is treated as described in the previous examples to separate the nitroiodide ICF CH(NO )OF CH C F 6 We claim: 1. Fluorinated nitrciodides of the formula ICF 'CHRNO Where R is a perfiuoroalkyl radical.

5. Fluorinated nitroiodides of the formula ICF CHRNO Where R is a fiuorohydroalkyl radical.

References Qited in the file of this patent Kuhn et al.: C.A., VOl. 54:20825(b) 1960 C- f. I-Ielv. Chim. Acta. 43, 607-17 (1960) QD1H4, copy in S.L. 

1. FLORINATED NITROIODIDES OF THE FORMULA 